Cost-efficient hosting and load balancing of Massively Multiplayer Online Games

Massively Multiplayer Online Games (MMOG) are a class of computationally-intensive client-server applications with severe real-time Quality of Service (QoS) requirements, such as the number of updates per second each client needs to receive from the servers for a fluent and realistic experience. To guarantee the QoS requirements, game providers over-provision to game sessions a large amount of their resources, which is very inefficient and prohibits any but the largest providers from joining the market. In this paper, we present a new approach for cost-efficient hosting of MMOG sessions on Cloud resources, provisioned on-demand in the correct amount based on the current number of connected players. Simulation results on real MMOG traces demonstrate that compute Clouds can reduce the hosting costs by a factor between two and five. The resource allocation is driven by a load balancing algorithm that appropriately distributes the load such that the QoS requirements are fulfilled at all times. Experimental results on a fast-paced game demonstrator executed on resources owned by a specialised hosting company demonstrate that our algorithm is able to adjust the number of game servers and load distribution to the highly dynamic client load, while maintaining the QoS in 99.34% of the monitored events.